Early parental loss in childhood and depression in adults: A systematic review and meta-analysis of case-controlled studies

Background: Many researchers have concluded that early parental loss during childhood is a risk factor for depression in late life of adults; however others didn't find any association. The objective of this systematic review is to assess whether this association exists or not by conducing a meta-analysis of published studies. Methods: Nine published case-controlled studies were chosen through literature searches in PUBMED, and LIBRARY GENESIS. Newcastle-Ottawa Scale (NOS) have been used to assess the quality of studies included. Thereafter, data were extracted from each study and analysed using ProMeta. Results: Nine case-controlled studies (representing n = 2784, cases = 716 and controls = 2068) were included in meta-analysis. The overall random effects model results of parental loss [OR = 2.18, 95% CI, 1.63-2.90, p < 0.00; I-2 = 15.79%, df = 8, p = 0.302], parental death [OR = 1.76, 95% CI, 1.13-2.73, p = 0.012; I-2 = 0.00%, df = 3, p = 0.600] and parental separation [OR = 3.14, 95% CI, 1.92-5.15, p < 0.001; I-2 = 0.00%, df = 2,p = 0.675] showed a strong positive effect on developing depression in adults. Egger's linear regression test [t = 0.14, p = 0.895] and Begg and Mazumdar's rank correlation test [z = 0.63, p = 0.532] confirmed absence of publication bias of studies included in this meta-analysis. Limitations: This systematic review was limited by a small number of case-controlled studies included in meta-analysis due to the differences in methodological designs of studies. Conclusion: The study concluded that parental loss, parental death, and parental separation before age 18 are risk factors of depression in adulthood.